Tractors Bigger Threats to Wildlife Than Climate: Study

Farming and hunting pose a more immediate threat to wildlife than climate change, researchers said, in a controversial plea to redirect resources earmarked for species conservation.

In an analysis of nearly 9,000 "threatened" or "near-threatened" species, scientists found that three-quarters are being over-exploited for trade, leisure or food.

Demand for meat and body parts, for example, has driven the Western gorilla and Chinese pangolin to near extinction, and pushed the Sumatran rhinoceros -- prized in China for the supposed medicinal properties of its horn -- over the edge.

And more than half of the plant and animal species in the study have suffered from the conversion of their natural habitats into industrial farms and plantations, mainly to raise livestock and grow commodity crops for fuel or food.

By comparison, only 19 percent of these species are currently affected by climate change, according to the study published in the peer-reviewed journal Nature.

Conservation priorities, the researchers said, must reflect this reality.

"Addressing the old foes of over-harvesting and agricultural activities are key to turning around the biodiversity extinction crisis," said lead author Sean Maxwell, a professor at the University of Queensland in Australia.

Climate change has overshadowed more traditional conservation priorities over the last decade, siphoning limited resources -- and cash -- away from more urgent needs, the authors argued.

But other conservationists were critical of both the Nature analysis, and the accompanying appeal.

"There is no need to see tradeoffs among different conservation priorities -- we need them all," Peter MacIntyre, an expert on the ecology of fresh-water systems at the University of Wisconsin, told AFP.

MacIntyre illustrated the point in a study, published this week, that fingered climate change -- as well as over-fishing and pollution -- for the depletion since 1950 of fish stocks in central Africa's Lake Tanganyika, a vital source of protein for millions.

"What good is it protecting a habitat that becomes oxygen-deprived or too hot for its current species due to climate warming, or where lake levels drop due to changes in precipitation patterns?", he asked.

The Nature analysis acknowledges global warming could become an increasingly dominant menace for biodiversity.

"But, overwhelmingly, the most immediate threat comes from agriculture and over-exploitation," said co-author James Watson, a biodiversity expert at the Wildlife Conservation Society.

Earth, he said, has now entered a "mass extinction event" in which species are disappearing 1,000 to 10,000 times more quickly than a century or two ago.

"It is hard to exaggerate just how dramatic the threat to Earth's species really is," Watson said.

Christopher Wolf, an expert on large carnivores at Oregon State University, agreed with the Nature analysis and noted that hunting and habitat loss are -- at least for big cats and wolves -- much greater dangers in the near term.

But all the pressures closing in on Earth's biodiversity do have one thing in common, he added: "all threats faced by species are caused by man."